Pneumatic percussion device for making holes in the ground by packing the latter

ABSTRACT

The invention consists in a pneumatic percussion device for making holes in the ground by packing the latter, comprising a striker accommodated in a tapered housing and adapted to deliver impacts upon the housing in the course of its reciprocation under the effect of compressed air intermittently supplied to working chambers of the device by a distributing mechanism formed by an air-supply pipe secured in the shank portion of the housing, on which pipe there is set a movable sleeve adapted to overlap one of the inlet apertures of the pipe, and openings in the shank portion of the striker, said openings being overlapped by the pipe during the striker movement.

United States Patent [72] Inventors U.S.S.R. Appl. No. 12,208 Filed Feb.19, 1970 Patented Nov. 2, 1971 Priority Feb. 26, 1969 U.S.S.R. 1307966PNEUMATIC PERCUSSION DEVICE FOR MAKING HOLES IN THE GROUND BY PACKINGTHE LATTER 4 Claims, 4 Drawing Figs.

Primary Examiner-James A. Leppink Attorney-Waters, Roditi, Schwartz &Nissen ABSTRACT: The invention consists in a pneumatic percussion devicefor making holes in the ground by packing the latter, comprising astriker accommodated in a tapered housing and adapted to deliver impactsupon the housing in the course of its reciprocation under the effect ofcompressed air intermittently supplied to working chambers ofthe deviceby a distributing mechanism formed by an air-supply pipe secured in theshank portion of the housing, on which pipe there is set a movablesleeve adapted to overlap one of the inlet apertures of the pipe, andopenings in the shank portion of the striker, said openings beingoverlapped by the pipe during the striker movement.

PATENTEDMuv 2 197:

SHEET 1 [IF 2 PNEUMATIC PERCUSSION DEVICE FOR MAKING HOLES IN THE GROUNDBY PACKING THE LATTER This invention relates to pneumatic percussiondevices for making holes in the ground by packing the latter and can beused to advantage in trenchless laying of pipes, electric and telephonecables, etc.

There are already known prior art devices, in particular, thosedescribed in French Pat. No. 1,515,348 and Belgian Pat. No. 695,405,featuring a cylindrical housing with a pointed front port onaccommodating a striker with a space in the shank portion thereof, saidstriker dividing the inside of the housing into front and rear workingchambers to which compressed air is intermittently supplied by adistributing mechanism for imparting reciprocation to the striker whichis delivering impacts upon the housing.

The air-distributing mechanism in said known devices comprises anair-supply pipe secured in the shank portion of the housing and openingsin the shank portion of the striker, said openings being intermittentlyoverlapped by the pipe when the striker advances thereupon with itsspace.

The air-distributing mechanism has been adapted to reverse the devicestroke owing to axial displacement of the air-supply pipe, making forsuch a variation in the striker of the housing.

The percussion energy of the known devices, at preset overall dimensionsthereof, is relatively low, for the pressure of compressed air in theforward stroke does not act upon the total cross-sectional area of thestriker but upon the cross-sectional area of its space.

It is an object of the present invention to provide a more powerful andefficient device, without changing its overall dimensions, by improvingthe air-distributing mechanism.

The present specification discloses such a device. In accordance withthe present invention, the pipe mounts a sleeve connected with thestriker and movable with respect to the latter and the pipe, while inthe sidewall of the pipe provision is made of an aperture connecting theair conduit of the pipe with the rear working chamber, said aperturebeing overlapped by the sleeve during the striker stroke towards thefront working chamber.

The sleeve mobility relative the pipe and the striker is attained due tothe provision on the sleeve of two outer ribs spaced from each other,between which ribs is arranged a pin secured to the striker and adaptedto alternately cooperate with said ribs.

Exhausted air can be alternately removed from the working chambers ofthe device during the striker movement, either via channel and exhausthole in the air-supply pipe or through an opening in the housing.

The provision of the movable sleeve and the air-supply aperture in thepipe to be overlapped by this sleeve has made it possible to supplycompressed air throughout the total crosssectional area of the strikerduring the forward stroke from the rear chamber and, during the reversestroke, to cut off the supply of compressed air to said chamber.

Presented hereinbelow is a detailed description of exemplary embodimentsof the present invention with reference to the accompanying drawings,wherein:

FIG. 1 shows the proposed device with a reversing air-distributingmechanism, the striker being in its position prior to the beginning ofthe forward stroke during the device advance;

FIG. 2 shows the same device at the moment of the striker impact, thatis, in the position prior to its reverse stroke;

F IG. 3 shows the same device, the striker being in the posi tion ofdelivering an impact upon the shank portion of the housing during thedevice retreat; and

FIG. 4 shows one of the possible embodiments of the proposed devicehaving a nonreversing air-distributing mechanism.

Now, referring to FIGS. l-4, a cylindrical housing 1, pointed in itsfront portion, accommodates a striker 2 dividing the inside of thehousing 1 into front, 3, and rear, 4, working chambers to whichcompressed air is intermittently supplied for imparting reciprocation tothe striker 2 which impacts upon the housing 1.

The striker 2 in its shank portion has a space 5 open from the butt endside, a space 5:: of smaller diameter and radial openings 6, while inthe shank portion of the housing 1 is secured an air-supply pipe 7connected to an air-supply main 8. During the movement of the striker 2,its radial openings 6 are intermittently overlapped by the pipe 7entering the space 5a, whereby intermittent air supply is attained tothe front 3 and rear 4 chambers.

In the sidewall of the pipe 7 provision is made of aperture 9 serving toconnect the rear chamber 3 with air conduit 10 of the pipe 7. Thislatter aperture can only be overlapped during the movement of thestriker 2 towards the front chamber 3 by a sleeve 11 mounted outside thepipe 7 and connected with the striker 2 so as to be movable with respectto the striker 2 and pipe 7.

To this end, the sleeve 11 is provided with two ribs 12 and 13 spacedfrom each other, between which ribs is arranged a pin 14 of the striker2, said pin alternately cooperating with the ribs 12 and 13 during thestriker reciprocation, whereby the sleeve 11 is caused to move and closeor open the aperture 9.

Thus, the pipe 7, the sleeve 11, the openings 6 and the aperture 9, whentaken in combination, form an air-distributing mechanism. Thanks to theprovision of the aperture 9, compressed air acts throughout the totalcross-sectional area of the striker 2 from the side of the rear chamber4, which results in an increase of the percussion energy of the strikerduring the forward stroke.

According to the embodiment of the present invention shown in FIGS. l-3,the above-mentioned pipe 7 is provided with a channel 15 designed forremoval ofexhausted air to the atmosphere and alternately communicating,during the move ment of the striker 2, with the chamber 3 and 41 viaexhaust hole 16 provided in the pipe 7. As seen from FIGS. 1 and 3, thepipe 7 is secured in the shank portion of the housing I by means ofa nut17 relative which it can be moved along thread 18.

By changing the position of the pipe 7 relative the nut 17, the momentof air supply to the working chambers 3 and 4 can be regulated so thatthe striker 2 will strike against the nut 17, thereby causing theretreat of the device. Reversing the device movement may be requiredwhen making vertical or blind horizontal holes, or for removing thedevice from the hole when encountering an obstacle (for example, aboulder), or in case the device has considerably deviated from a presetdirection.

The device shown in FIG. 4 only differs in that the discharge ofexhausted air is effected via opening 19 in the housing 1, while thepipe 7 is rigidly fixed in the nut 17. This device has a simpler design,however, its air-distributing mechanism is not adapted for reversing themovement ofthe device.

Presented hereinbelow is a description of the principle of operation ofthe proposed device during the forward and reverse strokes.

Let us consider the forward stroke of the device from the moment thestriker 2 and the sleeve 11 are in the extreme rear position, theaperture 9 of the pipe 7 is open, and the openings 6 of the striker 2are overlapped by the pipe 7, as shown in FIG. 1.

The chamber 3 is communicated with the atmosphere via the openings 6 ofthe striker 2, exhaust hole 16 in the pipe 7 and the air-dischargechannel 15 of the latter. Under the action of compressed air suppliedvia the: conduit 10 into the spaces 5 and 5a of the striker 2 andthrough the aperture 9 into the chamber 4, the striker 2 moves forward.When so doing, the pin 14 of the striker 2 acts upon the rib 12 of thesleeve 11, displacing the latter along the pipe 7 so as to overlap theaperture 9, thereby ceasing the supply of air into the chamber 4.Further advance of the striker 2 takes place under the effect of theenergy of air expanding in the chamber 4. At the end of the stroke thestriker 2 delivers an impact upon the is delivering front portion of thehousing 1, causing the latter to intrude into the ground.

Almost simultaneously with the impact, the exhaust hole 16 getsconnected with the space of the striker 2, as shown in FIG. 2, as aresult of which exhausted air is discharged into the atmosphere from thechamber 4 via the channel of the pipe 7, while the openings 6 getopened, and compressed air from the space 5a enters the chamber 3,causing the reverse motion of the striker 2.

The sleeve 11 remains in the extreme front position, i.e., the aperture9 is overlapped by this sleeve. During further movement of the striker2, its openings 6 are overlapped by the pipe 7 entering the space 50,and the supply of air to the chamber 3 is ceased. The striker 2 moves onowing to the energy of air expanding in the chamber 3.

As soon as the openings 6 of the striker 2 coincide with the exhausthole 16, there takes place the discharge of exhausted air to theatmosphere from the chamber 3 via the channel 15 of the pipe 7. Thestriker 2, moving on by inertia, acts with its pin 14 upon the rib 13 ofthe sleeve 11 which displaces to its initial position leaving theaperture 9 open for the subsequent air intake to the chamber 4.Thereupon, the cycle is repeated.

In order to switch the device over to the reverse stroke, the pipe 7should be displaced relative the nut 17 from the front to rear position,for example, by turning the main 8 until the pipe 7 is screwed into thenut 17 up to the stop, as shown in FIG. 3.

With the new position of the pipe 7, the openings 6 of the striker 2during the latter's advance will open earlier and, consequently, theintake of compressed air to the chamber 3 will take place earlier,therefore, the striker 2 will brake without having struck against thefront portion of the housing 1 and start moving in the oppositedirection. During this latter movement of the striker 2, the exhausthole 16 and the aperture 9 will open later, that is, the exhaust ofexhausted air from the chamber 3 and the intake of compressed air to thechamber 4 will take place later, and the striker 2, having no time forbraking, will deliver an impact upon the nut 17, as a result of whichthe housing 1 of the device will move in the opposite direction.

Thereupon, the cycle is repeated.

The device shown in FIG. 4 operates analogously during the forwardstroke, however, the discharge of exhausted air from the chambers 3 and4 takes place via exhaust opening 18 in the housing 1.

We claim:

1. A pneumatic percussion device for making holes in the ground bypacking the latter, comprising: a cylindrical housing pointed in itsfront portion; a striker having openings and a space in the shankportion, said striker dividing the inside of said housing into front andrear working chambers and adapted to deliver impacts upon said housingin the course of its reciprocation under the effect of compressed air; apipe for the delivery of compressed air to said chambers, secured in theshank portion of said housing and overlapping the openings of thestriker when the latter advances with its space upon said pipe; a sleevemounted on the pipe and connected with the striker and movable withrespect to the latter and the pipe; said pipe having in its sidewall anaperture communicating the air conduit of the pipe with the rear workingchamber and adapted to be overlapped by said sleeve during the strikerstroke towards the front working chamber.

2. A pneumatic percussion device according to claim 1, wherein thesleeve has two outer ribs spaced from each other, between which ribs isarranged a pin secured to the striker.

3. A pneumatic percussion device according to claim 1, wherein theair-supply pipe is provided with a channel designed for the removal ofexhausted air to the atmosphere and alternately communicating, duringthe striker movement, with the front and rear chambers via an exhausthole.

4. A pneumatic percussion device according to claim 1, in whose housingprovision is made of an opening designed for the discharge of exhaustedair to the atmosphere and alternately communicating, during the strikermovement, with the front and rear chambers.

1. A pneumatic percussion device for making holes in the ground bypacking the latter, comprising: a cylindrical housing pointed in itsfront portion; a striker having openings and a space in the shankportion, said striker dividing the inside of said housing into front andrear working chambers and adapted to deliver impacts upon said housingin the course of its reciprocation under the effect of compressed air; apipe for the delivery of compressed air to said chambers, secured in theshank portion of said housing and overlapping the openings of thestriker when the latter advances with its space upon said pipe; a sleevemounted on the pipe and connected with the striker and movable withrespect to the latter and the pipe; said pipe having in its sidewall anaperture communicating the air conduit of the pipe with the rear workingchamber and adapted to be overlapped by said sleeve during the strikerstroke towards the front working chamber.
 2. A pneumatic percussiondevice according to claim 1, wherein the sleeve has two outer ribsspaced from each other, between which ribs is arranged a pin secured tothe striker.
 3. A pneumatic percussion device according to claim 1,wherein the air-supply pipe is provided with a channel designed for theremoval of exhausted air to the atmosphere and alternatelycommunicating, during the striker movement, with the front and rearchambers via an exhaust hole.
 4. A pneumatic percussion device accordingto claim 1, in whose housing provision is made of an opening designedfor the discharge of exhausted air to the atmosphere and alternatelycommunicating, during the striker movement, with the front and rearchambers.